In a hydraulic shovel, a work machine comprising a bucket is typically operated by an operator operating an operating lever. At such times, it is difficult for the operator to determine whether, when digging a ditch of a predetermined depth or a slope of a predetermined grade, digging the target shape is being accurately performed only by observing the motions of the work machine. Thus, in the hydraulic shovel display system disclosed in Japanese Patent Application Laid-Open Publication 2004-68433, the positional relationship between the target digging surface and a bucket blade edge is displayed as an image on a monitor. A numerical value displaying the distance between the target digging surface and the blade edge of the bucket is also displayed on the monitor. An operator is thereby capable of properly operating to dig a predetermined target digging surface.